The term “tensegrity” was originally coined by futurist designer and inventor R. Buckminster Fuller in the 1960s to describe systems of tension elements (e.g., ropes, cables, or cords) and compression elements (e.g. bars, rods, tubes, or other rigid strut-type components) held in a state of static pre-stressed equilibrium to define a three-dimensional frame structure, wherein the compression elements generally do not touch each other. The pulling forces applied by the tension elements are resisted by the rigid compression elements, and a tensegrity system remains stable even against externally applied forces. The word “tensegrity” itself combines “tension” and “structural integrity.” Fuller's U.S. Pat. No. 3,063,521 (filed in 1959 and issued in 1962) covers various basic tensegrity concepts, and Fuller and others have patented many variations since then.
When properly designed and constructed, tensegrity structures have proven to be robust and durable. Pioneering sculptor Kenneth Snelson's well-known “Needle Tower” sculpture, constructed of metal tubes and wire, has stood outdoors at the Hirshhorn Museum in Washington, D.C. for decades. Tensegrity structures can be suitable for furniture as well. A line of tensegrity sitting stools named after Snelson is offered by designer Sam Weller (samweller.co.uk).
The tensegrity concept has been well developed and used frequently in the decades since the 1960s (and even before then, as some structures—including the London Skylon tower dating from 1951—employed some tensegrity principles even before the term was coined). Tensegrity is capable of enabling lightweight but robust structures combined with artful design; there are many designs for furniture, bridges, buildings, sports stadiums, toys, and other structures—large and small—that employ tensegrity principles.
But for all their benefits, most tensegrity structures remain rigid and poorly adapted to use upon irregular surfaces. The pre-stressed balance between tension and compression provides little freedom for movement. Because of this, tensegrity furniture is not often suitable for use outdoors. The Snelson stools referenced above, for example, remain flat and balanced only on a flat floor; on an inclined surface the entire structure including the seating surface will also be inclined and vulnerable to tipping over, and on an irregular surface the legs of the stool will wobble. This, unfortunately, also holds true for many other pieces of tensegrity furniture.
Accordingly, there is a need for an adaptive tension-compression structure based on tensegrity principles but more capable of being used on inclined and irregular surfaces. Such a structure would be easily adjustable to various support surfaces and yet remain strong and stable as furniture or as a base for equipment or other objects.